The present invention generally relates to beverages. More specifically, the present invention relates to methods and systems for dispensing foamed beverages.
Foam quality (e.g. stability, stiffness and appearance over time) and amount are important parameters for Cappuccino type beverages. Many believe that the best quality foam is created by hand, for example, in coffee shops and derives from frothing fresh milk by steam injection. A shot of express coffee is added to hot milk, and the foam is gently poured on top of the liquid part. The result is dense, stiff and stable foam with small bubble size distribution. However, this method of producing foam requires an experienced operator and also relatively long times to be accomplished. Further, because of preparation by hand, the consistency of the final products is strongly related to the operator's skills. Consequently, there is a need for a methods and equipment that can be easily be used to generate high quality foamed beverages.
U.S. Pat. No. 2,949,993 “Carbonated Coffee Beverage Dispenser” describes an apparatus that dispenses cold carbonated coffee beverages with desired crème on top. The liquids are delivered in a dispensing head where they are mixed and finally put in a cup. The patent claims that “to ensure that a proper crème is formed on top of each beverage, different dispensing sequences are required for each combination.” Numerous recipes are said to have been developed, but no information about the flow rates, dosing sequences or times are provided. The disadvantage of this patent is that it does not apply to Cappuccino type beverage foam, and no reference is made on foam quality and stability over time.
U.S. Pat. No. 4,388,338 “Method for Preparing Beverages in Portions” relates to a method for preparing a beverage in a vending machine. A premeasured amount of flavored powder is added in the cup. Two different streams of water are sent into the cup simultaneously. One stream of water is at high pressure and low flow rate, and a second stream has a lower pressurized water (slight overpressure) and higher flow rate. A final shower of water can by sprayed over the foamed beverage for rinsing down and dissolving any grains of flavored powder. Nevertheless, this patent fails to show the delivery of a beverage liquid at different viscosities (e.g. different product component-to-diluent ratios) during dispensing to improve foam or reduce delivery time.
U.S. Pat. No. 4,903,585 “Dispensing Coffee Having a Foamed Appearance” describes an apparatus for producing and dispensing a coffee from spray dried powders, with a thick layer of stable foam. The method of using the apparatus consists in creating the foam using a limited amount of cold water in the mixing chamber upon vigorous agitation (thus forming a foamed liquid coffee concentrate) and diluting the beverage with hot water without disrupting the foam. A disadvantage of this patent is that the process is not continuous because the foamed cold liquid concentrate needs to be diluted with hot water in the correct ratio before dispensing the beverage and therefore the delivery time might be sacrificed. Further, the hot water needs to be dispensed tangentially along the sidewalls of the mixing chamber to break the surface tension of the foam on the sidewalls and also the foam is not applicable for Cappuccino type beverages.
U.S. Pat. No. 5,803,320 “Carbonated Coffee Beverage Dispenser” describes a soda and coffee extract that are dispensed through the entire dispensing process. The improvement of the creme is largely caused by the soda and bicarbonation level of the soda. However, soda is undesirable in coffee based products because it gives an undesirable sparkling effect. This patent is also silent as to how the control of the ratio cycle is achieved for improving the foam or reducing delivery time.
There is therefore a need to provide methods and systems for producing a foam having an improved quality in a short period of time.